Blasting explosive



Patented June 8,1937 I I UNITED STATES 2,083,144 PATENT OFFICE Laud S. Byers, Glendale, Calif., assignor by mesne assignments, to Halafax Explosives Company, I Los Angeles, Calif a corporation of Delaware No Drawing.

3Glaims.

10 feet of the well-known black powder of com-' merce, while at the same time, producing to some extent, a shattering which characterizes the detonating explosives, such as dynamite.

The invention also contemplates a method of manufacture, which is characterized by simplicity and reduced cost, as will be more fully apparent from the description given hereinafter.

Explosives may be generally classified as being of a detonating, or of a deflagrating type, dyna- 20 mite being illustrative of the first group, and common black powder of the second. The detonating explosives, such as dynamite, are characterized' by substantially instantaneous combustion, a large volume of gas being generated (with an 2 accompanying high temperature) in an extremely short time interval. "The explosion is sharp and exerts a shattering effect. Such explosives are used to greatest extent, in hard rock mining. Defiagrating explosives such as black 30 powder, do not exert a shattering effect, but instead rend, push or lift, these results being partly caused by the slower rate of combustion and the absence of instantaneous gas generation. Black powders are used most extensively in mak- 35 ing cuts through sedimentary deposits and in quarrying, where shattering or the production of small fragments is to be avoided. In practice, the drill holes are filled with black powder, one or more sticks of dynamite or other detonating 2m explosive being introduced into each drill hole for the purpose of-insuring initiation of explosion,

- and to assist the black powder in its performance:

Black powder is manufactured from nitrates,

45 sulphur and charcoal, the ingredients being very finely ground under a pressure of from three to five tons. The finely pulverized ingredients are then further compressed to form cakes, and these are then broken up on'granulators or break- 50 ing-down machines, to produce a granular product which is then glazed. Heretofoi'e, it has been thought essential that all of the ingredients be very finely ground, in order to produce a final product of substantially homogeneous distribu- 55 tion of ingredients.-

I have discovered that it is not necessary to employ sulphur or charcoal (which give rise to noxious fumes upon explosion) nor is it necessary to subject all of the ingredients to the expensive and slow fine grinding. Moreover, it is Application August 27, 1934, Serial No. 741,726

not necessary that the product be glazed. I have discovered that, by the use of certain ingredients (specified in detail hereinafter), a freerunning powder-may be produced without fine grinding or glazing, the resulting product hav- 5 ing substantially twice the efllciency of black powder, weightfor weight. Moreover, the resulting product, although principally of a deflagrating type, has anfinherent partial detonating property which permits the use of my prod- .uct in quarrying or other blasting operations,

without the necessity of concomitantly using therewith a secondary explosive such as dynamite.

In general, my invention is based upon the dis- 5 covery that, when coarsely shredded wood of a substantially uniform particle size is mixed with sodium nitrate,-a chlorateand a liquid mixture of isomers of dinitrotoluene so that each particle of the coarsely shredded wood is more or less coated with a mixture of the other ingredients, the resulting product has the unusual and highly desirable characteristics -above referred to. In addition to these ingredients, an initiating agent such as manganese dioxide, an antacid such as 5 calcium carbonate or zinc oxide, and a waterresisting agent may be'incorporated.

By the term free-running powder reference is made t?) a granular material having the consistency of coarsesand, the material being capable of being poured through a relatively small opening such as a drill hole, and to fill such drfll hole without bridging or choking the opening.

It is an object of this invention, therefore, to disclose and provide a particular combination of ingredients whereby a free-running powder having defiagrating characteristics coupled with a degree of detonating characteristics, is produced.

Another object is to disclose and provide a free-running granular powder, the particles of which are substantiallyuncompressed and unglazed, said powder being free from nitroglycerine, sulphur and charcoal. \J

A further object is to disclose and provide a free-running deflagrating powder having a degree of detonating characteristics, which, weight for weight, has approximately 150 to 220- per cent the effectiveness of the well-known commercial black powder.

A still further object of the invention is to dis- 60 close and provide a simple, inexpensive method of manufacturing a free running powder of the defiagrating type. These and other objects,

uses and advantages of the invention will become apparent to those skilled in the art, in the following detailed description of the ingredients, their method of combination and the characsteristics of the resulting product. x The main ingredient of the explosive is sodium nitrate. The ingredient present in the next '60 largest proportion is coarsely shredded wood of a substantially uniform particle size, 1. e., the wood is free from fines or dust, and also free from large, very coarse particles. It has been 5 found that a wood shredded so that it will pass an 8-mesh sieve but be retained upon a 12 or 14- mesh sieve, will produce the unusual results characterizing my explosive. Although various types of wood may be used, spruce appears to give the best results. The wood and sodium nitrate total to more than 50% of the entire or total weight of the product, and for best results these two ingredients should amount to from about 60% to 68% of the total weight.

15 The balance of the mixture consists essentially of potassium chlorate and a liquid mixture of isomers of dinitrotoluene. The mixture of isomers of dinitrotoluene, which is capable of being successfully used in this explosive, has

a low crystallizing temperature. Crystallization should begin to be observed at temperatures below 60 F. and preferably at temperatures of about 50 to 52 F. Liquid mixtures having crystallizing temperatures of between 40 F. and

60 F. have been successfully used. Ordinarily, however, it is a liquid having a specific gravity of about 1.3. Most of the mixture should consist of the 124 and 1--26 isomers of dinitrotoluene, with but a minor proportion of meta isomers. The liquid should be free from sulfonic acids or free mineral acids. Preferably the liquid mixture should contain not more than about 2% of compounds or substances volatile at 100 C. It is to be remembered that nitrated hydrocarbons such as nitrobenzene cannot be effectively substituted for the mixture of isomers of dinitrotoluene, referred to hereinabove.

Although the liquid mixture of isomers of dinitrotoluene has the characteristics of an oil, and it does impart some water-resisting properties to the final product, such water-resisting properties may be enhanced by introducing some nitrocellulose into the liquid. Preferably nitrocellulose containing more than 12% of nitrogen should be used. Such nitro cottons are not soluble in a mixture of dinitrotoluene isomers of the character above described, but it has been found that if a solution of nitro cotton (containing more than 12% of nitrogen) is first made in a volatile solvent such as acetone, and the resulting 20 to per cent nitrated cellulose solution is then mixed with a liquid mixture of isomers of dinitrotoleune, the nitrocellulose will be retained in stable solution within the liquid after the solvent has evaporated. From about 3 to 8 per cent of the solvent-nitrocellulose solution by weight of the liquid mixture of isomers, can be thus made a part of the product.

The specific proportions in which'the various ingredients may be used, are as follows:

Per cent Coarsely shredded wood 29 to 31 Sodium nitrate 34 to 36 Potassium chlorate 16 to 18 65 Liquid isomers 14 to 16 Manganese dioxide 0.5 to 4 added to a mixture containing the required proportion of coarsely shredded wood, which has already been mixed with a suitable quantity of liquid isomers. Manganese dioxide or other initiating agent and antacid can be also added at this time, and the batch of ingredients is then thoroughly mixed until each of the particles of wood appears to be covered with an adhering coating of chlorate and nitrate. Any form of mixer may be used, although it has been found that mixers provided with helically disposed agitators mounted along a horizontally disposed shaft within a. cylindrical container or housing, are very emcient. The mixers should not exert an appreciable shredding or tearing action upon the fibers.

The product resulting from this operation is homogeneous and rather bulky, Weighing about 35 to 38 pounds per cubic foot. Weight for weight, the product of this invention produces substantially the same amount of breakage as commercial black powder, with the added advantage that detonating explosives such as dynamite, need not be used. Furthermore, the noxious gases which are developed upon explosion of black powder, are not generated upon explosion of the product of this invention. The product is safe to handle and can be tamped or rammed into drill holes readily. Although it is necessary to explode black powder charges electrically (because black powder will catch on fire from the fuse, but fail to explode), the powder of this invention can be exploded both electrically and by means of a fuse. The use of fuses is not recommended, however.

Although a very specific composition has been described hereinbefore, it is to be understood that minor changes in the proportions of the ingredients can be made. Such changes will, however, infiuence the explosive characteristics of the product. When a greater proportion of coarse wood is used, the explosive will lose its detonating characteristics and eventually will fail to explode. When the proportion of wood is decreased, the rending and lifting effect is greatly diminished, and if the change is increased in this direction the explosive may be rendered totally useless. Variations in type of wood, type of initiating agent and purity of the other ingredients may also influence the product, and may either permit or prevent changes in proportions of ingredients. All such changes, modifications and adaptations as come within the scope of the appended claims, are embraced thereby.

I claim:

1. A free-running granular explosive containing about 29% to 31% of wood particles of substantially uniform size, about 34% to 36% of sodium nitrate, about 16% to 18% of potassium chlorate and about 14% to 16% of liquid isomers of dinitrotoluene having an initial crystallizlng temperature of between 40 F. and 60 F., said wood particles being composed essentially of particles adapted to pass an B-mesh sieve and be retained on a I l-mesh. sieve.

2. A free-running granular explosive containing about 29% to 31% of wood particles of substantially uniform size, about 34% to 36% of sodium nitrate, about 16% to 18% of potassium chlorate, and about 14% to 16% of liquid isomers of dinitrotoluene having a crystallization temperature of between 40 F. and 60 F. and containing added nitrated cellulose in solution therein, said wood particles being composed essentially of particles adapted to pass an 8-mesh sieve and be retained on a. 14-mesh sieve.

3. A method of making a free-running granular explosive having the properties of blasting powder, coupled with an ability to exert a degree of shattering upon explosion which comprises:

adding a liquid mixture of isomers of dinitrotoluene having a crystallization temperature of between 40 F. and 60 F. to coarsely shredded wood composed essentially of particles adapted to 

